The present invention relates to adjustable ambulance cots, and in particular to trolley and latching mechanisms for adjusting such cots to different positions.
Conventional ambulance cots are provided with wheels to enable easy movement from one location to another, including rolling the cot into and out of an emergency vehicle such as an ambulance, van, station wagon, or modified truck. In their simplest forms, such cots have nonextensible wheels mounted beneath the cot frame.
More sophisticated types of ambulance cots also exist. Elevating cots are available in which the cot frame is mounted on legs which are designed to collapse as the cot is placed in the vehicle. Cots of this type may have two positions of use, or may have multiple adjustable positions. That is, such cots have a first "down" position in which the legs are fully collapsed and an elevated "up" position in which the cot is at a standard predetermined height for transferring the patient to a bed. Cots having adjustable positioning features may be positioned at a number of intermediate heights between the fully down and up positions. Cots have also been designed so that the legs collapse as the cot is loaded into the rear of an emergency vehicle such as an ambulance.
Necessary features of adjustable cots where the legs are designed to collapse relative to the cot frame are sliding and latching mechanisms which permit movement of the cot legs relative to the frame. For example, Ferneau et al, U.S. Pat. No. 4,767,148, teach a multiple level roll-in cot having an elongated locking bar and latch pin combination which releases the cot frame for elevation and lowering.
However, many of the current adjusting mechanisms used for adjustable cots require frequent periodic maintenance, lubrication, and cleaning to avoid malfunctions. Further, many adjustable mechanisms in current use have metal-to-metal contacts which require the presence of grease so that the mechanisms will not bind during adjustment of the cot height. Greased metal parts tend to attract and hold dirt and other debris which will soil the cot mattress or sheets as well as the clothing of technicians and patients who accidentally come into contact with those greased parts. The frequent maintenance requirements to clean these mechanisms and then reapply clean lubricants are both time consuming and labor intensive. Accordingly, there is a need in this art for cot adjusting mechanisms which have fewer maintenance requirements and yet which will operate smoothly and consistently during use.